Do you have any idea when your constructor is called? Do you know if it is called before or after Wire has been constructed? Before or after Wire is ready to do anything?
Where is the flashLED() method? Is the LED ready to be flashed when your constructor is called?
The initLCD() function assumes that Wire is ready to work. Do you know for a fact that it is?
I doubt that you know when your constructor is called, relative to the other constructors. Did you notice, for instance, that there is a Wire.begin() method, where the real work is done? Your class needs a begin() method, and (nearly) all stuff being done by the constructor needs to be moved to the begin() method.